Warning on furnace cleaning
Our home was built in 1950. It's a large home, with 4 zones, and a 250k btu hydronic heating system - natural gas - it's the original furnance.
About 5 years ago we began to smell a 'chimney odor' - I paid to have the fules inspected - all was good. Since the home has two fireplaces, it was suggested that since we don't burn wood - it's what was left from before.
Three years ago, I paid $300 to have the furnance cleaned.
Several months ago I noticed that there was soot around the the cover in the boiler vents. Also, my wife complained about a 'combustion smell'. CO / draft checks ok.
Last week, the pressure/temp gauge began to leak. I decided to fix it on the weekend. I took the cover off the side of the furnance - it really wasn't meant to be taken off - about a dozen screws.
The boiler consists of 8 segments - like a squared off radiator - between each segment there was a cast iron cover that covered the opening between boiler segments. One of these covers fell off, while I was removing the side of the furnance.
What I saw: The boiler was completely 'impacted' with scale and soot! I removed over 20 lbs of material from the boiler flues.
After a week, all is well, and the odor is gone. Apperently nobody ever cleaned the boiler after 60 years! I looked at my boiler cleaning bill - it doesn't say what they did.
I was lucky - I think the whole thing could have overheated in a much more serious way.